While astronomy is commonly taught in primary schools, there is abundant evidence of the persistence of misconceptions of astronomical phenomena. A core difficulty for students is the need to coordinate earth and space-centred perspectives in visualising and explaining astronomical phenomena. This chapter will describe an astronomy lesson sequence with 150 students from six Grade 1 (age 6 years) classes across two schools. The sequence links science with mathematics, with representation construction and modeling as core approaches to learning. Key features of the sequence were students’ construction and coordination of spatial representations. These were connected with the changes/movements in shadows (patterns) throughout the day and with the movement of the sun in the sky and with earth’s rotation in relation to the sun to explain day and night. The mathematics focus was on spatial reasoning including representations of length, rotation and angle, pattern representation, and temporal reasoning. Pre- and post-test data and student interviews showed considerable shifts in understanding of day and night and earth-sun relations. Analysis of the video data, and field notes, showed the complexity of concepts and spatial reasoning required, as well as the power of an interdisciplinary, guided inquiry pedagogy involving the construction, comparison and evaluation of concepts and representations.